1. Field of the Invention
The present invention relates to a method for transmitting facsimile data between facsimile apparatuses provided in sending side and reception side. Further, the present invention relates to relay apparatuses provided in the sending side and the reception side, and the relay apparatus of sending side is connected to the relay apparatus of reception side through an internet protocol network, or through a wide area network (WAN). In this case, not only facsimile apparatuses, but also sound data terminals are connected to the internet protocol network.
2. Description of the Related Art
When transmitting facsimile data through an internet protocol network, in a relay apparatus, for example, a router or a gateway, which is connected between the facsimile apparatus and the internet protocol network, the facsimile data are treated based on the same coding method as sound data, and transferred to a relay apparatus of destination, for example, a router or a gateway, based on a UDP (User Datagram Protocol).
In general, by using the UDP, it is possible to execute a protocol process with high speed and small overhead of the network so that it is possible to realize data transfer for which high immediate-transfer is required, for example, communication of sound data between sound terminals. In this case, however, since the UDP has no error correction function or re-transmission function, the reliability of this protocol is low.
The object of the present invention is to provide a method for transmitting facsimile data between facsimile apparatuses which can improve transmission quality of the facsimile data on the internet protocol network, and can realize uniform traffic load (or circuit load) on the internet protocol network so that it is possible to prevent deterioration of throughput due to overload of the traffic load on the whole of the internet protocol network.
Another object of the present invention is to provide a relay apparatus provided in the sending side and the reception side, and the relay apparatus of the sending side is connected to the relay apparatus of reception side through an internet protocol network, or through a wide area network (WAN). In this case, not only facsimile apparatuses, but also sound data terminals, are connected to the internet protocol network.
In accordance with a first aspect of the present invention, a method for transmitting facsimile data between a facsimile apparatus of a sending side and a facsimile apparatus of a reception side, the facsimile apparatus of the sending side being connected to a relay apparatus of the sending side, the facsimile apparatus of the reception side being connected to a relay apparatus of the reception side, and the relay apparatus of the sending side being connected to the relay apparatus of the reception side through an internet protocol network, includes steps of:
performing an address conversion from a telephone number of a facsimile apparatus of the reception side, which is transmitted from a facsimile apparatus of the sending side when setting a call, to an IP address corresponding to the telephone number;
transmitting a request for establishment of TCP connection including a flow control and re-transmission function, to a relay apparatus corresponding to a destination of the IP address, when receiving an identifying signal which indicates transmission of the facsimile data from the facsimile apparatus of the sending side; and
transmitting the facsimile data to the relay apparatus corresponding to the destination of the IP address based on the TCP connection.
In a preferred embodiment, the above step of transmitting the request for establishment of the TCP connection comprises a step of transmitting a particular port number, which indicates transmission of the facsimile data, with the request for establishment of the TCP connection.
In another preferred embodiment, the above step of transmitting the facsimile data based on the TCP connection comprises a step of comparing a circuit load in the internet protocol network with a threshold value which was previously determined based on a service level for communication for transmitting the facsimile data, and transmitting the facsimile data when the circuit load is smaller than the threshold value.
In still another preferred embodiment, the above step of transmitting the facsimile data based on the TCP connection comprises a step of controlling transmission timing of the facsimile data based on transmission timing which was previously determined in accordance with the circuit load and service level of communication.
In accordance with a second aspect of the present invention, a relay apparatus connected to facsimile apparatuses and further connected to an internet protocol network, includes:
an address conversion unit for performing an address conversion from a telephone number of a facsimile apparatus of the reception side, which is transmitted from a facsimile apparatus of the sending side when setting a call, to an IP address corresponding to the telephone number;
transmitting unit for transmitting a request for establishment of TCP connection including a flow control and re-transmission function, to a relay apparatus corresponding to a destination of the IP address, when receiving an identifying signal which indicates transmission of the facsimile data from the facsimile apparatus of the sending side; and
a transmitting unit for transmitting the facsimile data to the relay apparatus corresponding to the destination of the IP address based on the TCP connection.
In a preferred embodiment, the unit for transmitting the request for establishment of the TCP connection comprises a structure of transmitting a particular port number, which indicates transmission of the facsimile data, with the request for establishment of the TCP connection.
In another preferred embodiment, the unit for transmitting the facsimile data based on the TCP connection comprises a means for comparing a circuit load in the internet protocol network with a threshold value which was previously determined based on a service level for communication for transmitting the facsimile data; a unit for transmitting the facsimile data when the circuit load is smaller than the threshold value; and a means for temporally accumulating the facsimile data.
In still another preferred embodiment, the unit for transmitting the facsimile data based on the TCP connection comprises a unit for controlling transmission timing of the facsimile data based on transmission timing which was previously determined in accordance with the circuit load and service level of communication.